In an internal combustion engine, after the power stroke is completed, there are two agents of waste that are left in the fuel burning cylinder at the bottom of the power stroke; pressure and heat. The pressure is what was created by burning the fuel, expanding the air that was collected in the cylinder during the intake stroke. By burning the fuel in the presence of this air which was compressed during the compression stroke, the heat rapidly increases the energy in the air molecules, creating pressure that forces the piston down during the power stoke. At the end of this power stroke, the wasted pressure that still remains in the fuel burning cylinder and the heat are exhausted into the atmosphere during the exhaust stroke. A gasoline engine is approximately 30% thermodynamically efficient, which equates to 70% of the potential energy in gasoline being wasted, either by not using all the air pressure that was created, or by not using all the heat energy that was developed during the 4 stroke internal combustion cycle.